Sir.—Lanes et al1 reported in AJDC that 64% of normal growth hormone (GH) secretors responded to an oral dose of 50 μg of clonidine hydro
chloride, whereas 90% of a similar group of children responded to 100 μg of clonidine hydrochloride. This statistically significant difference conflicts with two previously published letters, which indicated that a dose as low as 25 μg produced an adequate GH response in the pediatric age group.2,3
Our results (Table) support the conclusions of Lanes and his colleagues. When we administered an oral dose of 25 μg if the child weighed under 47.5 kg and 50 μg if the child was over this weight, only three of 12 normal boys between the ages of 10 and 16 years had an unambiguous response to clonidine. This compares with seven of 12 who responded to 500 mg of levodopa. The order of drug administration was